UBUNTU-CVE-2020-10932

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UBUNTU-CVE-2020-10932

Summary:

Details: An issue was discovered in Arm Mbed TLS before 2.16.6 and 2.7.x before 2.7.15. An attacker that can get precise enough side-channel measurements can recover the long-term ECDSA private key by (1) reconstructing the projective coordinate of the result of scalar multiplication by exploiting side channels in the conversion to affine coordinates; (2) using an attack described by Naccache, Smart, and Stern in 2003 to recover a few bits of the ephemeral scalar from those projective coordinates via several measurements; and (3) using a lattice attack to get from there to the long-term ECDSA private key used for the signatures. Typically an attacker would have sufficient access when attacking an SGX enclave and controlling the untrusted OS.

References: https://ubuntu.com/security/CVE-2020-10932, https://tls.mbed.org/tech-updates/releases/mbedtls-2.16.6-and-2.7.15-released, https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-04, https://tls.mbed.org/tech-updates/security-advisories, https://www.cve.org/CVERecord?id=CVE-2020-10932